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<title>Berkeley DB Reference Guide: Release 4.0: memp_XXX</title>
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<td><b><dl><dt>Berkeley DB Reference Guide:<dd>Upgrading Berkeley DB Applications</dl></b></td>
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<p align=center><b>Release 4.0: memp_XXX</b></p>
<p>The C API for the Berkeley DB Memory Pool subsystem was reworked in the 4.0
release as follows:</p>
<table border=1 align=center>
<tr><th>Historic functional interface</th><th>Berkeley DB 4.X method</th></tr>
<tr><td>memp_register</td><td><a href="../../api_c/memp_register.html">DB_ENV-&gt;memp_register</a></td></tr>
<tr><td>memp_stat</td><td><a href="../../api_c/memp_stat.html">DB_ENV-&gt;memp_stat</a></td></tr>
<tr><td>memp_sync</td><td><a href="../../api_c/memp_sync.html">DB_ENV-&gt;memp_sync</a></td></tr>
<tr><td>memp_trickle</td><td><a href="../../api_c/memp_trickle.html">DB_ENV-&gt;memp_trickle</a></td></tr>
<tr><td>memp_fopen</td><td><a href="../../api_c/memp_fcreate.html">DB_ENV-&gt;memp_fcreate</a></td></tr>
<tr><td>DB_MPOOL_FINFO: ftype</td><td><a href="../../api_c/memp_set_ftype.html">DB_MPOOLFILE-&gt;set_ftype</a></td></tr>
<tr><td>DB_MPOOL_FINFO: pgcookie</td><td><a href="../../api_c/memp_set_pgcookie.html">DB_MPOOLFILE-&gt;set_pgcookie</a></td></tr>
<tr><td>DB_MPOOL_FINFO: fileid</td><td><a href="../../api_c/memp_set_fileid.html">DB_MPOOLFILE-&gt;set_fileid</a></td></tr>
<tr><td>DB_MPOOL_FINFO: lsn_offset</td><td><a href="../../api_c/memp_set_lsn_offset.html">DB_MPOOLFILE-&gt;set_lsn_offset</a></td></tr>
<tr><td>DB_MPOOL_FINFO: clear_len</td><td><a href="../../api_c/memp_set_clear_len.html">DB_MPOOLFILE-&gt;set_clear_len</a></td></tr>
<tr><td>memp_fopen</td><td><a href="../../api_c/memp_fopen.html">DB_MPOOLFILE-&gt;open</a></td></tr>
<tr><td>memp_fclose</td><td><a href="../../api_c/memp_fclose.html">DB_MPOOLFILE-&gt;close</a></td></tr>
<tr><td>memp_fput</td><td><a href="../../api_c/memp_fput.html">DB_MPOOLFILE-&gt;put</a></td></tr>
<tr><td>memp_fset</td><td>DB_MPOOLFILE-&gt;set</td></tr>
<tr><td>memp_fsync</td><td><a href="../../api_c/memp_fsync.html">DB_MPOOLFILE-&gt;sync</a></td></tr>
</table>
<p>Applications calling any of the memp_register, memp_stat, memp_sync or
memp_trickle functions should update those calls to use the enclosing
<a href="../../api_c/env_class.html">DB_ENV</a> handle's method (easily done as the first argument to the
existing call is the correct <a href="../../api_c/env_class.html">DB_ENV</a> handle).</p>
<p>In addition, the <a href="../../api_c/memp_stat.html">DB_ENV-&gt;memp_stat</a> call has been changed in the 4.0
release to take a flags argument.  To leave their historic behavior
unchanged, applications should add a final argument of 0 to any calls
made to <a href="../../api_c/memp_stat.html">DB_ENV-&gt;memp_stat</a>.</p>
<p>Applications calling the memp_fopen function should update those calls
as follows: First, acquire a <a href="../../api_c/mempfile_class.html">DB_MPOOLFILE</a> handle using the
<a href="../../api_c/memp_fcreate.html">DB_ENV-&gt;memp_fcreate</a> method.  Second, if the DB_MPOOL_FINFO structure
reference passed to the memp_fopen function was non-NULL, call the
<a href="../../api_c/mempfile_class.html">DB_MPOOLFILE</a> method corresponding to each initialized field in
the DB_MPOOL_FINFO structure.  Third, call the <a href="../../api_c/memp_fopen.html">DB_MPOOLFILE-&gt;open</a> method
method to open the underlying file.  If the <a href="../../api_c/memp_fopen.html">DB_MPOOLFILE-&gt;open</a> method call
fails, then <a href="../../api_c/memp_fclose.html">DB_MPOOLFILE-&gt;close</a> method must be called to destroy the allocated
handle.</p>
<p>Applications calling the memp_fopen, memp_fclose, memp_fput, memp_fset,
or memp_fsync functions should update those calls to use the enclosing
<a href="../../api_c/mempfile_class.html">DB_MPOOLFILE</a> handle's method.  Again, this is easily done as the
first argument to the existing call is the correct <a href="../../api_c/mempfile_class.html">DB_MPOOLFILE</a>
handle.  With one exception, the calling conventions of the old and new
interfaces are identical; the one exception is the <a href="../../api_c/memp_fclose.html">DB_MPOOLFILE-&gt;close</a> method,
which requires an additional flag parameter that should be set to 0.</p>
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